Starting and operating circuit and device for electric discharge devices



Feb. 19, 1952 p, WAGUET 2,586,403

STARTING AND OPERATING CIRCUIT AND DEVICE FOR ELECTRIC DISCHARGE DEVICES Filed June 16, 1948 Inven=lrow-z Philippe Wzzguei'. 5; W?

Patented Feb. 19, 1952 STARTING AND OPERATING CIRCUIT AND DEVICE FOR ELECTRIC DISCHARGE DE- VICES Philippe Waguet, Paris, France, assignor to General Electric Company, a corporation of New York Application June 16, 1948, Serial No.33,385

In France June 14, 1947 3 Claims. (Cl. 315-165) 1 This invention relates to electric discharge devices of the type employing ionizable mediums 'such as gases or vapors and more particularly to starting and operating devices and circuits therefor.

An object of my invention is to provide a new and improved starting and operating circuit for electric discharge devices energized from a direct current source.

Another object of my invention is to provide an improved and simplified operating circuit for luminous electric discharge devices or fluorescent lamps energized from a direct current source, and utilizing an auxiliary dependent alternating voltage source for heating the electrodes and starting the discharge in the lamps.

My invention is of general applicability wherever it is desired to operate fluorescent lamps from a direct current supply. It has been found particularly useful in vehicles andrailroad cars, particularly in cars which are illuminated as a unit and which do not require separate illumination for individual compartments.

A feature of my invention is the utilization of an auxiliary direct-to-alternating current converter for heating the filamentary electrodes in the lamps, and also for starting the discharge. This is achieved by means of a time-delay relay which permits the utilization of the induced voltage, resulting from the rupture of the field winding circuit of the converter, as a starting impulse for the lamps.

For a more complete discussion of various circuits which may be utilized in operating fluorescent lamps from a direct current supply, reference is made to my copending U. S. application No. 28,223, filed May 20, 1948. Other applications and improvements in such circuits are disclosed in my copending U. S. applications Nos. 28,224, 28,225, and 28,226, filed May 20, 1948, and 33,386 and 33,387, filed June 16, 1948. All of the above applications are assigned to the same assigneeas the present application.

For a better understanding of 'my invention, reference may be had to the following description taken in connection with the accompanying drawing and its scope will be pointed outin the appended claims. The drawing is a diagrammatic view of a plurality of electric discharge devices connected in parallel and a starting and operating device and circuit therefor incorporating my invention.

Referring to the drawing, I have there illustrated one embodiment of my invention as applied to electric discharge devices I, 4'. The. electric discharge devices I, I, such asfiuorescent lamps therein illustrated comprise elongated tubular or cylindrical envelopes 2, 2' having sealed into the ends thereof filamentary electrodes 3, 4 and 5, Ii. These filamentary electrodes may comprise coils, preferable in the form of coiled coils of tungsten wire activated with oxides of alkaline earth metals, such as a mixture of barium and strontium oxides. The envelopes 2, 2' may contain gaseous atmospheres such as a rare gas like neon, argon or mixtures thereof at a pressure of a few millimeters and a small quantity of mercury which, during the operation of the lamps, has a low pressure of the order of 10 microns. Devices I, I'-may be low pressure positive column lamps of a fluorescent type provided with a suitable phosphor or fluorescent coating. This fluorescent coating upon excitation by the radiation produced by an electric discharge between the electrodesjtransforms a shorter wave radiation due to the discharge into longer wave radiation such as radiation within the visible range. Metal cups I, 8 and 9, I0 serve to intercept the particles of emissive material sputtered from electrodes 3, 4 and 5, 6, respectively. These cups are usually tied by means of connections, either outside or insideof the lamps, to the ex tremities of the electrodes. A number of advantages result from the connections between the electrodes and the corresponding cups, namely, utilization of the cups 8 and II! as anodes and eliminating the disintegration by ionic bombardment of electrodes 4 and 6, utilization of lamps that are usually employed with alternating current discharge circuits, reduction of operating voltage, doubling the life of lamps by using successively the two filamentary electrodes, i. e., by turning the lamps around when one of the filaments becomes inoperative.

Devices I, I' are connected across a suitable direct current power supply circuit II, II for supplying current thereto through stabilizing resistances I2, I2. Resistances I2, I2, for example, may be iron or tungsten wire enclosed in hydrogen. A manual make-and-break control switch I3 may be used to connect devices I, I to the power supply II, II. A starting and operating circuit I4, I4 is connected across the direct current supply I I, I I and comprises a field winding section I5 of a dynamoelectric machine or rotary converter I6 and a switching means I! comprising a normally closed contactor I8 and a normally open contactor I9-. -Auxiliary electrodes 20, 20" mounted adjacent devices I, I, re-

: spectively, areconnected toa common pointZI intermediate field winding section 15 and contactors l8 and I9 of switching means 11. The time-delay relay or switching means i! further comprises a coil 22 connected across the terminals of the direct current source H, I I through the manual make-and-break switch l3, and a normally closed contactor 23 and a normally open contactor 24 in series with an armature winding section 25 of the dynamoelectric machine I6 across the direct current supply H, H.

A transformer 26 comprising a primary winding section 21 and a center-tapped secondary winding section 28 is connected across an alternating current supply 29, 29' produced by the dynamoelectric machine IS. The secondary winding section 28 of transformer 26 serves to heat filamentary electrodes 3 and and to continue to heat these electrodes as long as primary winding section 21 is energized. The center-tap of the secondary winding section 28 is connected to the negative side of the direct current source II, II by means of switch l3.

The circuit illustrated in the drawing operates as follows: In the rest or inactive position contactors l9 and 24 are open and contactors I8 and 23 are closed. As soon as switch I3 is closed, coil 22 of relay or switching means 11 is energized, contactor I9 closes and thus energizes field winding section l5 of the dynamoelectric machine it; contactor 24 then closes with a time delay of a few tenths of a second with respect to the closing of contactor l9, and applies voltage to the armature winding section 25 of the dynamoelectric machine I6. Upon energization of the armature winding section 25, the dynamoelectric machine l6 begins to rotate and energizes transformer 26. Cathode filamentary electrodes 3 and 5 are then heated; after a few seconds, contactor 23 opens, breaking or interrupting the circuit of the armature winding section 25 and discontinues the heating of cathode filamentary electrodes 3 and 5. A few tenths of a second after the opening of the contactor 23, contactor 18 opens and interrupts the starting circuit l4, M which embodies the field winding section [5 of the dynamoelectric machine IS. The rate of change of current through the field winding section creates a voltage impulse which is applied to point 2! and in turn imparted to the auxiliary electrodes 20, As a result of this impulse the discharge devices I, l are ignited.

The retarded functioning of contactors i8, i9, 23 and 24 of relay or switching means I! may be obtained, for example, by means of a mechanism which is actuated by coil 22 and which causes the tilting of two glass bulbs containing mercury whose flow is suitably slowed down by a capillary tube and thus serves to establish or break the contacts. Another manner of actuating contactors l8, i9, 23 and 24 in sequence may be obtained by varying the magnetic force required to actuate these contactors by space relationship of the contactors with relation to the coil 22 and by varying the tension with which each individual contactor is maintained either opened or closed, as the case may be.

While a certain specific embodiment has been shown and described, it will, of course, be understood that various modifications may be made without departing from the invention. Thus, whereas one particular type of converter has been described, other types may be used, providing they comprise the essential elements of an armature and a separately excited field winding. Likewise, various other switching devices, either mechanical or electrical, may be substituted for the time-delay relay which has been described. The appended claims are, therefore, intended to cover any such modifications coming within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for operating a gaseous luminous electric discharge device, of the type including a main thermionic electrode and a cooperating main electrode comprising: said device, a unidirectional voltage source, and a ballast resistance; a rotary converter having a direct current field winding, a direct current input winding, and an alternating current output winding; connections from said output winding to said thermionic electrode for heating same; a discharge circuit constituted by connecting said device, in series with said ballast resistance, across said source; a timedelay relay having two sets of contacts respectively connecting said field and input windings across said source, said relay operating to energize in sequence, first said field winding and then' said input winding, and said relay then operating to de-energize in sequence after a predetermined time interval, first said input winding and then said field winding; and an auxiliary starting electrode on said device connected to the junction of said field winding with the associated contact of said relay.

2. Apparatus for operating a gaseous luminous electric discharge device, of the type including a main thermionic electrode, a co-operating main electrode, and an auxiliary starting electrode in-- termediate the ends thereof, comprising: said device, a unidirectional voltage source, and a ballast resistance; a rotary converter having a direct current field winding, a direct current input winding, and an alternating current output winding; connections from said output winding to said thermionic electrode for heating same; a discharge circuit constituted by connecting said device, in series with said ballast resistance, across said source; a time-delay relay having two sets of contacts respectively connecting said field and input windings across said source, said relay operating to energize, in sequence,. first said field winding and then said input winding, and said relay then operating to de-energize in sequence after a predetermined time interval, first said input winding and then said field winding; and a connection from said auxiliary electrode to the junction of said field winding with the associated contact of said relay for applying the voltage induced in said field winding upon de-energizing, to said device as a starting impulse.

' 3. Apparatus for operating a plurality of fluorescent lamps, of the type including a main filamentary thermionic electrode and a cooperating main electrode, comprising: said devices, a unidirectional voltage source, and a plurality of ballast resistances; a dynamoelectric machine for converting direct current to alternating current, said machine comprising a field winding and an armature having direct current input terminals and alternating current output terminals; connections from said alternating current output terminals, through a transformer, to said filamentary electrodes for heating same; discharge circuits constituted by connecting said lamps, each in series with one of said ballast resistances. across said source; a time-delay relay having two sets of contacts respectively connecting said field winding and said input terminals across said source, said relay operating to energize, in seacacnoa interval'fsuflicient to permit heating of said filamentarylele'ctrodes, first said armature and then said field winding; and auxiliary starting electrodes, f located intermediate the ends of said lamps, connected to the junction of said field mndiniwith the associated contact of said relay PHILIPPE WAGUET REFERENCES CITED The following references are of record in the file of this patent:

Number Number 0 UNITED s'n 'ms mm're Name Date Von Wedel July 14, 1931 Wiegand Feb. 9, 1932 Erickson Oct. 16, 1934 Lederer Nov. 12, 1935 McKesson Mar. 25, 1941 Lord Aug. 19, 1941 Campbell Dec. 21, 1948 Mills Feb. 22, 1949 FOREIGN PATENTS Country Date France Oct. 22, 1940 

